Excavation

The gravel was removed from the end of the marsh behind the last baffle and dirt was excavated directly behind the end of the marsh to a depth of approximately 4 feet. Any water in the marsh was removed using a 1 1/2" Bilge Hand Pump and a bucket (see Figure 7d). The beginning of the irrigation trench was also excavated. Tank #3 was then placed in the hole. This tank was placed vertically with its base approximately level with the bottom of the marsh. The marsh and the barrel were connected through piping a few inches above their bases using a bulk head union. The gravel was replaced between the last baffle and Tank #3. The gravel throughout the marsh was redistributed evenly.

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  Fig 7a: To begin end use renovation, removing the rocks and water from the area after the last baffle was necessary
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  Fig 7b: And we needed a place to put all those stinky rocks
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  Fig 7c: The water that had gathered at the end of the system with no place to go
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  Fig 7d: Removing the water with a bilge pump
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  Fig 7e: Irrigation trenching begins
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  Fig 7f: Main stem of irrigation system

Surge Tank

The Surge Tank (aka Tank #1) was initially designed as the settling, filtration, and FOG catching tank. The plan was to have a sock filter attached to the initial greywater outlet from the house and a siphon system to draw water from the barrel and over to Tank #2. The issue with a sock filter is that it requires frequent maintenance and often needs to be replaced. The Oasis Graywater Design Manual states that the "drum with pump and mesh filter [bag] is pretty much a discredited technology at this point due to longevity problems." We have changed the purpose of Tank #1 to be a surge tank with a metal mesh filter to catch large debris. This required that the barrel be raised approximately three feet to bring the bottom of the barrel just a few inches below the inlet and outlet pipes. This will provide at least two feet of surge capacity and will encourage water to flow rapidly through the piping over to Tank #2.

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  Fig 8a: Location of the surge tank with supporting earth already raised to six inches below the outlet pipes from the house.
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  Fig 8b: Unattached surge tank with connection pipe fittings.
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  Fig 1: Fitting the surge tank back into place.
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  Fig 8c: Surge tank with sealed connections.
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  Fig 8d: Surge tank filter that easily slides on and off outlet pipe from tank.
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  Fig 8e: Surge tank sealed connection pipe fitting.
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  Fig 8f: Completed surge tank with filter connected to the tank outlet pipe.
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  Fig 8g: Completed surge tank with concrete and filter next to outlet pipe.

Settling Tank

The settling tank (aka Tank #2) was initially designed as the surge tank. Hinges were added to the maintenance opening and the existing duct tape was removed. A larger maintenance opening was added, also with hinges and a latch. This tank mimics a restaurant grease trap with an aluminum baffle trapping the FOG on the water surface, while letting the underlying water flow underneath this baffle, free of FOG, out and into the marsh. This baffle will also slow down the water and allow sediment to settle at the bottom of the tank. The outlet pipe from Tank #2 was attached to the pond liner using a bulk head union (see fig. 9b).

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  Fig 9a: The aluminum we formed into the baffle to be fit in the settling tank.
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  Fig 9b: Water-tight union between the pump coming from the settling tank and the rubber marsh liner.
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  Fig 9c: Settling tank without metal baffle.
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  Fig 9d: Settling tank with metal baffle.

Water Testing Tank

Initially improvements were focused on the end-use portion of the marsh system. This required the addition of a water testing site (aka Tank #3) for the cleaned water exiting the marsh. This water will then exit the tank and continue on through an irrigation system to water landscaping plants in the southwest corner of the CCAT property. A blue 55-gallon barrel was donated by CCAT for use as Tank #3. The water testing tank has several functions. The primary function is an access point to the water once it has been cleansed by the biological and physical processes occurring in the marsh for water quality testing. Additional functions are to allow adjustments to be made to the height of the water in the marsh using piping and to be a connection and access point for the beginning of the irrigation system.

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  Fig 10a: The location of tank #3
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  Fig 10b: The interior of tank #3
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  Fig 10c: Piping to allow for adjustment of marsh water height, which is attached to the outlet pipe from the marsh on the inside of tank #3
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  Fig 10d: The final exterior look of tank #3

Mosquito Prevention

Each tank would have some standing water and needed protection from mosquitoes. We gathered some fiberglass mesh, 16 gage wire, and a two inch spring to create protective barriers around the tank openings.

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  Fig 11a: The springs and wire used for the mosquito screens.
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  Fig 11b: The settling tank with plastic door closed and mesh screen secured.
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  Fig 11c: The settling tank with plastic door open and mesh screen secured.
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  Fig 11d: Shows one of the screws that washers are placed over to secure the screen.
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  Fig 11e: Testing tank with mesh screen secured.
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  Fig 11f: Mesh screen clasp open. Loose wire is placed through the open side of the spring and bent back over itself away from the spring.
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  Fig 11g: Mesh screen clasp closed.
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  Fig 11h: Testing tank with mesh screen and plastic lid secured.
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  Fig 11i: Surge tank with mesh screen.
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  Fig 11j: Surge tank screen clasp.
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  Fig 11k: Surge tank with mesh screen and metal lid secure.

Irrigation System

The gravity-fed irrigation system was built to provide water for several alkaline-tolerant plants at the southwest corner of the CCAT property. The irrigation begins at the marsh outlet water testing barrel (aka Tank #3) and flows through ABS piping in a branching pattern at various depths underneath the soil. The depths range from 6" to 4'-0" underneath the surface of the soil. In this system there are 5 outlet points with water being released through holes that were drilled into the last 2' of each pipe branch. These perforated pipes were surrounded by gravel and held in place by heavy rocks or bricks. Dirt was then replaced over the top of the pipes and compacted by walking. 2" to 6" rocks were placed over the branches and main stem of the system to indicate for future users where the pipes are located and as an art piece. The main stem of the system continually slopes gradually downward, while the branches have either a neutral or negative slope.

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  Fig 12a: Irrigation trenches
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  Fig 12b: Irrigation pipe layout
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  Fig 12c: Fitting the pipes into the trenches
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  Fig 12d: Piping support
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  Fig 12e: Gravel filler
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  Fig 12f: Covering piping with soil
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  Fig 12g: Adding rocks to highlight the piping layout on surface of soil. This adds an artistic element to the system and allows for easy location of the system for maintenance.
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  Fig 12h: Placing rocks around tank #3 to cover the pond liner.

Landscaping

Drought tolerant California native plants were used to landscape the area between the rock wall on the east side of the marsh. These plants will only be receiving rain water after establishment (2 years). Prior to establishment, these plants will need to be watered weekly the first year and monthly the second year. Water loving, alkaline tolerant plants were used to landscape the area receiving the treated gray water. These included small trees, shrubs, and ground covers. Our focus was to use plants that provided food, such as berry bushes or orchard trees. The plants used were: (1) Apple tree, (1) Currant: Ribes speciosum (3) Monkey flowers: Mimulus aurantiacus, (4) Evergreen huckleberries: Vaccinium ovatum, (4) Toyon: Heteromeles arbutifolia, and (2) Coffeeberry: Rhamnus californica. The coffeeberry shrub starts were too small to plant right away and are maturing in their pots as of May 2009. Two rose bushes were already planted on-site and will remain in place.

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  Fig 13a: Dwarf apple tree
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  Fig 13b: Seep monkeyflower shrub
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  Fig 13c: Evergreen huckleberries that will provide yummy purple berries
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  Fig 13d: Evergreen current
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  Fig 13e: Toyon shrub
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  Fig 13f: Completed terrace landscaping without mulch
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  Fig 13g: Sedum groundcover terrace planting with mulch

System Activation

There are two valves directly north of the surge tank that turn the water flowing into the greywater system and the sewer system flow on or off from the house (see fig. 14a). If the greywater valve is closed and the sewer valve is open (fig. 14b), the greywater will flow directly into the sewer. If both valves are closed (fig. 14c), the greywater will flow into the house and out the floor drain in the basement bathroom. If the greywater valve is open and the sewer valve is closed (fig. 14d), all of the greywater will flow into the greywater marsh system. If the greywater valve is open and the sewer valve is open (fig. 14e), the greywater will split equally between the greywater and sewer systems due to the plumbing configuration. A gadget (fig. 14f) was made to switch the valves on and off from two pieces of wood. This gadget is inserted all the way into the valve access pipe and fits over the top of the valve handle. The gadget is then turned, using the handle, the desired direction (fig. 14g).

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  Fig 14a: Sewer and greywater on/off valves.
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  Fig 14b: Sewer ON and greywater OFF.
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  Fig 14c: Sewer OFF and greywater OFF.
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  Fig 14d: Sewer OFF and greywater ON.
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  Fig 14e: Sewer ON and greywater ON.
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  Fig 14f: Key to help turn the valves.
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  Fig 14g: The key fits over the valves and is turned using the handles.
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  Fig 14h: Diagram of the different settings for the system activation valves.

Signage

Soap warning and reminder for CCAT household: Soap Recommendations

Testing

1. Next steps would include water testing from the surge and/or settling tanks as compared to the water in the marsh and then in the final collection tank (tank #3) before the water is released for irrigation.
2. Testing the soil around the vegetation absorbing water from the irrigation system should also be done and compared to the surrounding soil to determine whether or not the greywater is lowering the pH and adding salt compounds to the soil.

Maintenance

• Here is a comprehensive maintenance video: http://www.youtube.com/watch?v=PQsiXyZn2a0
• Surge tank filter to be cleaned twice a month with adjustments as needed.
• FOG (Fats, Oils, and Grease) will need to be cleaned from the settling tank at least twice a month, depending on CCAT cooking habits.
• The surge tank and settling tanks will need to be completely drained and cleaned once a year.
• The water level in the marsh will need to be adjusted every three months from lower to higher to encourage different levels of root growth.
• The rocks in the marsh will need to be replaced every 5-10 years as based on water quality testing results.
• The landscaping plants will need to be watered twice a month for the first year and once a month during the second year. After the second year, the plants will only need to be watered during a sustained drought period or if they appear to need another year of watering before they are established enough to rely only on the weather.
• http://www.harvestingrainwater.com/greywater-harvesting/greywater-compatible-soaps-and-detergents/

Recommended Improvements

• The baffle in the settling tank may be too small and too low in the barrel. This will need to be observed over time to determine its effectiveness or lack thereof.
• In the irrigation system there are check valves to help distribute the water more evenly between the various outlets. Access pipes should have been placed above them to the top of the soil for future maintenance and adjustment.
• The surge tank will have approximately three inches of greywater sitting inside of it, which is significantly less from the original design, but will still likely turn in to blackwater if the system is left unused for any period longer than 24 hours. The main issue with this will be smell. Concrete has already been added to the tank in order to reduce the amount of excess space. We would recommend an additional fitting to further reduce the extra space. This could be made out of rocks, foam, or more concrete, but the filter will still need to be able to be easily removed and replaced.
• The plumbing in tank #3 has parts that have not been glued to allow for easy adjustment to the level of water in the marsh. As the system ages it may be more effective to have screwing parts or to glue more of the pieces together.
• The fencing around the surge tank and the marsh will need to be replaced or reinforced by Fall of 2009.
• Stairs or easier access points to the surge tank and the settling tank also need to be constructed.